In vitro propagation of human transitional cell malignancy (TCM) has proven difficult. Present tissue culture methodology does not reliably produce long term cell cultures. TCM has successfully been implanted in Swiss nude mice where it can be maintained and propagated. TCM, obtained at surgery, will be (a) implanted in nude mice and (b) placed into in vitro tissue culture. The primary tumors, and those obtained from in vivo (nude mice) propagation will be studied to determine the stromal contribution to in vitro maintenance and propagation of human transitional cell malignancy. A stock of human TCM will be maintained in nude mice. In vitro assay of the effectiveness of various chemotherapeutic agents can be conducted in short-term tissue culture. Dispersed cells of primary TCM will be placed in microtiter plates and assayed for the ability of selected chemotherapeutic drugs to inhibit cellular dehydrogenase activity. The ability of the same agents to effect tumor regression in the nude mouse tumor system, using the identical tumor, will be determined. When appropriate, these same agents used singularly, or in combination, will be given to patients demonstrating measurable metastatic disease and the clinical response recorded and correlated with the in vitro response.